| 摘要 |
This application addresses the problem of performance degradation caused by steering errors in a steered least squares adaptive beamformer 101 of a receive system. The least squaes beamformer may take the form of a linearly-constrained minimum output power (LCMP) beamformer implemented as a generalised sidelobe canceller (GSLC) using the Griffiths-Jim algorithm. The invention monitors the covariance 6 between the envelope of the signal, d, output from the least squares beamformer and the envelope of the signal at an internal point in the least squares algorithm. Preferably the internal point is at the auxiliary inputs Y for controlling filter weights within the least squares algorithm. Based on the covariance estimates, steering corrections 7 are applied to a beam steering vector, S0. The steering corrections also take account of the statistical dependence of the signals themselves. The invention has applications in the fields of wireless signal transmission, radar, optical systems, speech and sonar. |
